Electric rotating machines comprise an armature rotor and an inductive stator mounted in coaxial fashion, the stator surrounding the rotor. The rotor is integral with a drive shaft rotating inside a yoke. The stator has a plurality of magnetic poles disposed on an internal circumferential surface of a yoke and made up of salient poles around which are wound inductive wires, the unit constituting a wire wound inductor. The rotor, placed at the centre of the stator, comprises armature wires wound in notches.
The inductive poles of the stator generally have “shoes”, that is to say lateral extensions at their apex as on a capital letter T.
Wire wound inductors are particularly prone to a strong armature reaction due to their polar parts, this effect being much more pronounced than in the case of an inductor with permanent magnets. Indeed, salient poles contribute to amplifying the induction resulting from the magnetomotive force of the armature and their shoes reinforce the deformation effect of the induction lines due to the inductor, by providing a path and a material preferential for the induction lines due to the armature, these being perpendicular to those of the inductor at this point. This leads to the armature reaction effects being amplified, whereas usually the aim is to reduce them.